Process for working up stretched filaments of aromatic polyesters of high molecular weight



Dec. 8, 1964 R. KRETSCH PROCESS FOR WORKING UP STRETCHED FILAMENTS OF AROMATIC POLYESTERS OF HIGH MOLECULAR WEIGHT 2 Sheets-Sheet 1 Filed Jan. 30, 1962 INVENTOR ATTORNEYS Dec. 8, 1964 R. KRETSCH 3,159,964

PROCESS FOR WORKING UP STRETCHED FILAMENTS OF AROMATIC POLYESTERS OF HIGH MOLECULAR WEIGHT Filed Jan. 30, 1962 2 Sheets-Sheet 2 NVE NTOR. ms K/PETSt'H BY w g 5, ATTORNEYS.

3,159,964 Paocnss son wonmNc ur srnnrcnnn sna- NEENTS {BF ARGMATIC PGLY$TERS OF TH GH MOLECULAR WEIGHT Ros! Kretsch, Bobingen, near Augsburg, Germany, assignor to Farbwerke l-loechst Ahtiangeseilsehaft .vormais Meister Lucius Briining, Frankfurt am Main, Germany, a corporation Germany Filed Jan. 349, 1962, Ser. No. 169,782 Claims priority, application Germany, Feb. 11, 1961, F 33,189; Mar. 17, 1%1, F 33,434

llClaims. (til. 5715'7) Between rollers 5 and8, which serve as fixed points and around which the filament is wrapped several times,.; the filament is allowed to Shrinkby 5 to 35%. The filament is then fed to a further rollerlt) having a higher speed than roller 8 so that between roller 8 and roller 10 the filament is stretched by 5-35%. Subsequently the filament is wound up on bobbin 14.

The present invention relates to a process and apparatus for working up stretched filaments of aromatic polyesters of high molecular weight.

Filaments of aromatic polyesters of high molecular weight have hitherto been worked up in discontinuous manner by twisting the stretched filaments and Winding v them upon a bobbin, the core of which consists of an elastic wirestructure. The wound-up filaments are then subjected on the bobbin to a prolonged steam treatment, whereby shrinkage occurs and the filaments are simultaneously set. After said heat-setting the filaments are wound up on saleable bobbins.

The present invention provides a process and an appara tus which enable stretched polyester filaments to be worked up into a finshed saleable for-m inone continuous operation. According to the process of the invention the stretched filament is twisted ad the twisted filament is passed through a solution, dispersion, or emulsion of at least one substance boiling within the range of 120 C. to 350 C. and then fed to two rollers, which serve as fixed points and rotate at different speeds and around each of which the filament is passed several times, the first of the rollers being heated. Between these rollers, the'filament is heated on all sides uniformly to a temperature within the range of 220 C.'to 350 C., preferably 250 C. to

280 C., for 0.1 m5 seconds, advantageously 0.2 to 1 second, and tallowedto undergo an adjustable shrinkage of 5 to preferably 1025%. Thereupon the filament is stretched again by the same degree or a higher P degree or a smaller degree and wound up on a bobbin. In general the after-stretching is carried out in a manner such that the finished filament possesses the most favorable shrinkage on boiling and thermo-sh'rinlcage required for the further processing in the weaving and knitting mill, so that a setting of the filament can be dispensed with. The term shrinkage on boiling indicates the degree of shrinkage in percent a filament undergoes when dipped into boiling Water. By the term thermo-shrinkage there is to be understood the degree of shrinkage a filament undergoes when kept for a few seconds in hot air of 200 C. 'If the filament is after-stretched by the same degree or a higher degree, it is of advantage to treat it with steam or dry hot air.

FIG. 1 is a diagrammatic view of'one embodiment according to the invention.

FIG. 2 is a diagrammatic view of another embodiment according to the invention. I

FIG. 3 is a diagrammatic view of still another embodiment according to the invention.

The process of the invention can be carried out as 7 follows: (cf. FIGURE 1 of the accompanying drawings)..

The stretched filament of linear aromatic polyesters. is

Wound up on a cop which is placed on a spindlelfrois charged with a treating liquid; The filament is then.

dried on heated roller 5 and-passed through heater 7 having a temperature within the range of 220 C. to 350 C.

A further mode of execution of the process of the 111- vention is illustrated. with reference to FEGURE 2.

' The filament is twisted and passed through the treating 7 liquid as described above. Subsequently, it is dried on heated roller 5, passed through heating channel 7 (temperature 220 -C.350' C.) and fedto roller 8 rotating at a lower speed. Between roller 5 and roller 8 the filament is allowed to shrink by the desired degree. The filament is then passed to a third roller 10' whichis mounted as stepped roller on roller 5. Stepped roller..10"rotates at a higher speed than roller 8 so that the filament is stretched between roller 8 and the stepped roller to a .de

, substance boiling within the range of 120 C. and 350C.

which can be removed later on by washing or has the.

character of a preparation and is therefore not detrimental i if it remains behind on the filament. The, chemical nature of the substance is only of minor importance. Decisive are its physical properties. A wide variety of substancesv I may therefore be used for carrying out the process of the invention. The substances should boil at a temperature in the range of 120 C; to 350 C.; at room temperature they may be fluid, syrupy, pasty or may form films. Crystalline substances of low molecular weight are less suitable for use since they deposit on the rollers. A well suitable substance is, for example, sorbitol, a sugar alcohol which is syrupy at room temperature. Besidesthere may be used other monoor polyhydrichigh-boiling alcohols, such as glycerol, lauryl-talcohols, glycols, and polyglycols. Furthermore, there may advantageously be used substances containing one or several reactive groups, for example hy-. droxyl or curboxy-l groups, as well as substances that-are tree from reactive groups and swell the polyester filament, for example high-boiling esters, high-boiling ethers or aromatic high-boiling hydrocarbons such as diphe'nyl. Still further, there are suitable for wetting the filaments higher molecular monoor di-carboxylicyacidsas far asv they do not decompose at a temperature above 200 C., and the esters thereof, for example terephthalic acid di butyl ester or tricresyl phosphate; high-boiling phenols,

amines and amino-alcohols, for example ethyl-amines, di-

ethanolamines and triethanolamines, as far as they do not produce yellowing of the filaments on heating; polymeric compounds, for example polyacrylic acid and the esters thereof, polymethylacrylic acid, polyvinyl alcohols and esters of polyvinyl alcohols. The solutions, emulsions or dispersions are advantageously prepared. with the use of water or an organic solvent boiling below C.

By adding a dyestufi to the treatment bath the filaments are simultaneously dyed, or by adding an optic-albrightener, forexample a substance of the following formula;

' the degree of whiteness of the filarnents is improved.

Patented Dec. 8., 1964 i stances listed above.

' It is also possible to apply a sizing agent to the filaments by adding such'sizing agent to the treating bath. Excel lently sized filaments are obtained, for example, with the use of emulsions of acid polyacrylic acid esters.

When filaments shall be prepared which have an especially good dyeability and an improved handle and gloss, it is of advantage to use, instead of filaments having a round cross section, filaments having a larger surface area, such as filaments the cross section of which has the shape of a triangle, star, dumb bell and the like. Underthe same conditions of treatment, filaments of this kind absorb a larger quantity of dyestutf than filaments having a 'round cross section so that it is possible to obtain very dark dyeings withoutthe use of carriers. 7 In special cases it may be advantageous to treat filaments of polyethylene terephthalate having a low viscosity,

for example a specific viscosity-tin the range of 0.450 to 0.7.00. 'By specific viscosity there is to be understood the to the filaments not after the twisting but already, together with the spinning preparation. It is recommended to use substances, such as high-boiling esters or hydroxyethyiated acids, which are suitable as spinning preparation as well as for improving the dyeability. The spun filaments which have been treated with such a spinning preparation arestretched as usual, twisted on the spindle of the apparatus of the invention, again treated with a solution or emulsion of the same compounds as used as spinning preparation,

ing chambers '7 and. 112' which is then passed twice by the filament.

The filaments treated by the process of the invention are finished and can be well dyed with dispersion dycstufiisa Furthermore, the treated filaments possess good textile properties. It is possible, for example, to adjust their shrinking values as desired, depending on the degree of heated at a temperature of above 220 C. while being allowed to shrink and finally stretched again.

Another variant of'the process of the invention con-fv sists in 'allowingthefilament of linear aromatic polyesters to shrink in a 'continuousoperationat a temperature in illustrated with the aid of the accompanying FIGURE 3.

A stretched polyester filament is twisted with the aid of twisting spindle 1, passed through thread guide 2 and introduced into treating bath 4 which is charged with a solution, dispersion or eniulsionof at least one of the sub- The filament -is' impregnated with said substances and dried on heated roller 5. The filament is thenpassed through heating chamber 7 where it is allowed to shrink by 5-35 since roller 8 rotates. slower The filament travels to than roller 5 by. this degree.

roller 10' which is mounted as stepped roller on roller 5.

The diameter of stepped roller 10' can be equal to or smaller than thatof roller 5. The stepped roller rotates at a higher speed than rollenS so that the filament is stretchedbetween roller 8 and roller,l0"by an'adiustable The filament is subsequently excellently dyed with dispersion dyestulfs.

rte-stretching. The high elongation which is undesired for many applications is reduced by the re-stretching.

The following examples serve to illustrate the invention but they are not intended to limit it thereto.

7 Example I A stretched filament of polyethylene terephthalate having a titer of 100/ 50, which was wound up on a cop, was

twisted to obtain'350 trs./m.-and then passed at room temperature through a bath containing 15% of glycerol dissolved water. The filament was then fed at a speed of 50 m./minute to a drying-roller which. was heated to' 100 C. and to which belonged an intermediate roller, the

filament being wrapped 12 times around said latter roller. I The filament then travelled through a heating chamber filament was wound up. The twisted filament thus obtained was ready for sale and of very good quality. It had a much better dyeability than comparative filaments made from the same cop which had been separately 'twisted' V and heat-set with hot steam.

On dyeing with the bromination product of 1,5-dianiino- 4,S-dihydroxyanthraquinone the filament absorbed 55.5% of the dyestuff used.

V 'ExampleZ Stretched filaments of polyethylene terephthalate having a titer of 100/50 were twisted and further treated .as f described in Example 1.

of 15% strength in water, there was used a 15 solution 'of sebacic acid dimethyl ester inethanol.

Instead of the glycerol solution The drying roller was heated at 80 C. and rotated at a speed of .50 m./minute, while the second'rollerhad a speed of only 35 m./minute. Thus the filament was allowed to shrink by 30% on this distance.

ment the filament was heat-set for 20 minutes, at 110 C. with steam. .The filaments obtained could be well dyed with dispersion dyestuffs. On dyeing as described: in Example l, the filaments absorbed 65.0% of the .dyestufi used.

Example 3 Stretched filaments of polyethylene .terephthalate hava titer of 100/50 were twisted and further treated as described in Example 1. The treating bath consisted of a 15% solution of te-rephthalic acid dibutyl ester in methanol. The first rollerwas heated at 80 C. and rotatedat a speed of 50 nil/minute while the' second roller had a speed of 35 m./ minute so that the filaments were allowed to shrink by 30%. The'third roller rotated at a speed of 40 m./minute whereby the filaments were again stretchedJ The resulting filamentscouldbe On dyeing as described in Example 1 the filaments absorbed 89.0%

winding-uplS the filament-is again allowed .to shrink in a v heating zone 12 by an adjustable degree.- When the two shrinkages are effected at the same temperature, it is pos- 0f the dyestutf used. I

- Example 4 Stretched filaments of polyethylene terephthalate hav-. 'lng a titer of /50 were-twisted andtreated as de-- scribed in Example 1 with a'glycerol solution of 15% strength. The first roller was heated at 100' C.'and ro- The filament was then stretched again by 30% and ,wound up. After said treatthe filaments were heat-set for- 20 minutes with hot dry air having a temperature of 180 C. On dyeing as described in Example 1, the resulting filaments absorbed 53.5% of the dyestufi used.

Example 5 Stretched filaments of polyethylene terephthalate having a titer of 100/50 and a specific viscosity of 0.620

were twisted as described in Example 1 and treated with a glycerol solution. The first roller was heated at 100 C. and rotated at a speed of 50 m./minute,the second roller had a speed of 40 m./minute. In the heat ing chamber heated at 250 C. the filaments were allowed to shrink by and then stretched again. The filaments obtained absorbed 74.0% of the dyestufi used when dyed as described in Example 1.

Example 6 Stretched filaments of polyethylene terephthalate having a titer of 75/35 and a star-shaped cross section (5 points) were twisted as described in Example 1 and treated with a glycerol solution. The first roller was heated at 100 C. and rotated at a speed of 50 m./minute, while the second roller had a speed of m. /minute so that the filaments could shrink by 30% in the heating chamber having a temperature of 250 C. The third roller had a speed of m./rni'nute whereby the filaments were stretched again. The resulting filaments were distinguished by an excellent dyeability with dispersion dyestuffs. They absorbed 89.5% of the dyestuff used when dyed as described inExample l. Fabrics made from the filaments had a nice silky gloss.

Example 7 Stretched filaments having a titer of 75/35 of polyethylene terephthalate (specific viscosity 0.620), the individual capillaries of which had a cross section in the form of a star with five points, were twisted as described in Example 1 and treated with a 15 glycerol solution. The first roller which was heated at 100 C. rotated at a speed of 40 m./n1inute and the second roller had a speed of 32 m./minute so that the filament was allowed to shrink by 20% in the heating chamber having a temperature of 250 C. The filaments were then stretched again. The resulting filaments absorbed 74.5% of the dyestuif used when dyed as described in Example 1.

' Woven or knitted articles made from the filaments possessed a wonderful silky gloss.

Example 8 of 35 m./minute so that the'fiiament shrunk by 30% in the heating chamber having a temperature of 250 C. The third roller rotated at a speed of m./minute whereby the filaments were stretched again. The filaments obtained showed an excellent receptivity for dispersion dyestuffs. When dyed as described in Example 1 they absorbed 87.0% of the dyestufi used.

The first roller was heated at 100 C. and rotated at a speed" of m./minute while the second roller had a speed 6 I v Example 9 A filament of polyethylene terephthalate having a titer of 50 was twisted and then passed through an emulsion consisting of 6% of dioctyl sebacate, 6% of a condensation product from oleyl alcohol with 5 mols of ethylene oxide and 3% of a condensation product from lauric acid with 7' mols of'ethylene oxide in water. The filament was dried on a roller heated at 100 C. around which. the filament was wrapped 12 times. The roller had a speed of 50 n1./rninute.: The filament was then passed through a heating chamber 45 cm.- long which had a temperature of 250 C. and subsequently wrapped 12 times around a second heated roller rotating at a speed of 35 m./minute so that on the Way through the heating chamber between the two rollers the filament was allowed to shrink by 30%. The filament was then reconducted to a third roller mounted as stepped roller on the first roller, heated at 100 C. and rotating at a speed of 50 m./minute. Thus the filament was stretched by the degree it previously shrunk. It was then passed a second time through the heating chamber having a temperature of 250 C., and wound up. The windingup device had a speed of 40"rn./rninute so that the filament was again allowed to shrink by 20%. The filament obtained was heat-set. It shrunk by 2.4% in boiling water and 3.64% in hot air of 200 C. In a dye bath containing as dyestufi 3% of the bromination prodnet of 1,5-diarnino 4,8 dihydroxyanthraquinone (calculated on the Weight of the filament) the filament absorbed, in the absence of a carrier, 79.0% of the dyestufl used.

Example 10 A filament of polyethylene terephthalate; having a titer of 100/50 was twisted as described in Example 9 and 250 C. by 30%, against stretched in the cold by 30%,

allowed to shrink a second time at 250 C. by 25% and then wound up. The finnished filament was set. It shrunk by 2.3% in boiling water and by 4% in air of 200 C. On dyeing as described in Example 9, the filament absorbed 90% of the dyestufi" used.

I claim: i 3

1. A process for processing stretched filaments of aromatic polyesters of high molecular weight, which comprises twisting the stretched filament s, passing the twisted filament through a bath consisting of a member selected from the group consisting of a solution, dispersion and an emulsion of at least one substance boiling in the range of C. to 350 C., feeding the filament to two rollers which serve as fixed points and rotate at ditferent speeds, the first one of which is heated, wrapping the filament.

several times around the rollers and heating it between the rollers uniformly on all sides to a temperature within the range of 220 C. to 350 C. for 0.1 to 5 seconds, simultaneously allowing the filament to undergo an adjustable shrinkage of 5 to 35%, again stretching the filament and winding it up, said steps beingcarried o one continuous operation.

2. The process oflcla'im 1, wherein the twisted filament is heated .to a temperature within the range of 250 C. to 280 C.

3. The process of'claim 1, wherein the filament is 3.1-.-

lowed to undergo an adjustable shrinkage of 10 to 25%.

4. The process of claim 1, wherein the bath consists of a member selected from the group consisting of, a f monofunctional reactive compound and a polyfunctional reactive compound.

5. The process of claim 1'; wherein at least-one disperi sion dyestufi is'a'dded to the bath in addition to the reactive compound. l

6. The process of claim 1, wherein an optical brightener is added to the bath.

tin

7. The process of claim 1, wherein the optical bright ener is a substance corresponding to the formula 8. The process of claini 1, Whichcomprises re-stretching the shrunk filament by the same degree as it shrunk previously and then winding it up.

' 9. The .process of claim, '1, which comprises re-stretch-- ing the shrunk filament by a smaller degree than it previously shrunk and-winding it up.

10. The process of claim 1, which comprises: re-stretchthe re-stretched filament in a continuous process at atemperature in the range of 220 C. to 350 C.-by allowing it to shrink again by a smaller degree than'that of the previous re-stretching, and Winding it up.-

References Cited in the, file of this patent UNITED STATES PATENTS 2,466,808 Henning et'al; Apr. 12, 1949 2,768,057 Friederich j Oct. 23, 1956 2,807,863, 'Schenker Oct. 1, 1957 2,846,752 Lessig Aug. 12, 1958 2,932,078 Wilson Apr. 12, 1960 

1. A PROCESS FOR PROCESSING STRETCHED FILAMENTS OF AROMATIC POLYESTERS OF HIGH MOLECULAR WEIGHT, WHICH COMPRISES TWISTING THE STRETCHED FILAMENTS, PASSING THE TWISTED FILAMENT THROUGH A BATH CONSISTING OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF A SOLUTION, DISPERSION AND AN EMULSION OF AT LEAST ONE SUBSTANCE BOILING IN THE RANGE OF 120*C. TO 350C., FEEDING THE FILAMENT TO TWO ROLLERS WHICH SERVE AS FIXED POINTS AND ROTATE AT DIFFERENT SPEEDS THE FIRST ONE OF WHICH IS HEATED, WRAPPING THE FILAMENT SEVERAL TIMES AOURND THE ROLLERS AND HEATING IT BETWEEN THE ROLLERS UNIFORMLY ON ALL SIDES TO A TEMPERATURE WITHIN THE RANGE OF 220*C. TO 350*C. FOR 0.1 T 5 SECONDS, SIMULTANEOUSLY ALLOWING THE FILAMENT TO UNDERGO AN ADJUSTABLE SHRINKAGE OF 5 TO 35%, AGAIN STRETCHING THE FILAMENT AND WINDING IT UP, SAID STEPS BEING CARRIED OUT IN ONE CONTINUOUS OPERATION. 